La Salle R&D benefits from several facilities and equipment, which allow performing a large variety of audio, acoustics and vibration measurements. Concerning the equipment, the DTM has at its disposal, among others, a multichannel real time spectrum analyser with its corresponding transducers (microphones and accelerometers), impact hammers, a tapping machine, a vibration exciter and a dodecahedral loudspeaker. In what refers to facilities, the DTM has a full anechoic chamber, a reverberation chamber and a full equipped recording studio. A more detailed description of these facilities is next provided.
Full anechoic chamber:
The anechoic chamber is used to conduct acoustic measurements in free field conditions. All sound energy emanating from a source inside the chamber propagates with none reflecting back. This is achieved by recovering the chamber with acoustically absorbent material arranged in pyramidal disposition. Vibration isolators separate the chamber form the rest of the building to avoid any structure-borne noise path that could alter the anechoic properties of the chamber. The anechoic chamber has a volume of 215 m3 (517 m3 without absorbent material), a cutoff frequency of 70 Hz and a residual noise of 15dB(A) (further technical specifications can be provided under request).
The reverberation chamber is used to perform acoustic experiments in diffuse field conditions. The chamber has been designed so as to have a high reverberation time (TR60) for all frequency bands. Inner walls are non-parallel, recovered with acoustically reflecting materials and several diffusers hang from an irregular shaped roof. Consequently, only a very small percentage of energy is lost at each reflection. The chamber has a volume of 231 m3, a total surface of 211 m2 and a floor surface of 44.6 m2. The residual noise is 16 dB(A) and the octave bands reverberation times are Frequency [Hz]/TR60 [s]: 125/11.5 250/11 500/10.5 1000/10 2000/7.25 4000/5 8000/2.25 (further technical specifications can be provided under request).
The recording studio consists of two separate spaces: the control room and the recording room. The control room hosts the hardware that the sound engineer uses to perform sound recording and mixing tasks. The studio is based on a digital sound platform and allows simple intercom between control and recording room. The room is acoustically treated with perforated wooden panels with absorbent materials on the inner side. The objective of these panels is to make the room’s frequency response as neutral as possible to ensure maximum transparency for the monitoring of recorded audio signals. The recording room is where musicians, speakers or other artists are recorded. To reduce the impact of room modes on the recording, the room’s ceiling has been made non-parallel to the floor. The absorbent curtains, together with the installed resonators allow having different acoustic environments that can be easily configured. There also is an acoustic door that connects the recording room to the reverberant chamber, which can be used to record special reverberation effects (technical specifications on th equipment being used at the recording studio can be provided under request).